I saw somebody advertising the material for sale on Ebay, and then I found the following posting using Google regarding the use of copper shim material:
I also did a search on Google: Using copper shim on a laptop gpu and scored pages and pages of info.
I bought (but haven't installed) a used/tested 441695-001 Motherboard, a T7600 Chip, annd (2) X 2GB Memory and was thinking this might be a worth while tweak/upgrade for longevity.
Hobby shops that cater to RC Airplane Builders sell pure copper sheets, and I have one right up the street ;-)
Also thinking of getting a 12 cell battery pack so as to rase the rear of the laptop and thus increase airflow.
Thoughts and experiences are welcome :-)